JPH0723552A - Spindle motor - Google Patents

Abstract

PURPOSE:To allow easy and highly accurate assembling of motor by driving an externally threaded fixing stud planted on the housing of a spindle motor into an internally threaded hole made in the bottom of the housing through a slit made at the upper end of the stud by means of a driver. CONSTITUTION:A sleeve 22 is born rotatably through a pair of bearings 3, 4 fixed vertically to the fixing stud 2 planted in a hole 43 at the boss part 17 provided in the center on the bottom of the housing 8. A hub 1 is externally fitted to the sleeve 22 in order to rotate a magnetic disc 10 mounted thereon. The fixing stud 2 is externally threaded 26 at the lower end part thereof and the internally threaded 25 holes 43 are made in the boss part 17 at same pitch. The stud 2 is then driven by means of a driver through a slit 27 made at the upper end of the stud 2 while elongating laterally from a hole part 31 thus butting the lower end face 49 at an annular step 21 of the stud 2 and the upper end face 46 at the boss part 17. This structure allows highly accurate and easy assembling of miniature motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor used for rotationally driving a recording disk such as an optical / magnetic disk.

[0002]

2. Description of the Related Art As a spindle motor used in a recording disk driving device such as a magnetic disk or a magneto-optical disk, there is a motor called a shaft fixed spindle motor shown in FIG. 3, for example. This shaft-fixed spindle motor includes a hub a to which a recording disk (not shown) is mounted,
Fixed support b, housing c, and a pair of bearing members f and g
, A stator d, and a rotor magnet e. The housing c, which is a stationary member, is mounted and fixed to a fixed frame (not shown) of the disk drive device with reference to a predetermined mounting position. A pair of bearings f and g are fitted to a fixed support b that is integrally fixed to the housing c and erected, and the hub a is rotatably supported via the bearings f and g. A required number of disks are mounted and fixed on the hub a. A rotor magnet e is mounted inside the hub a, and a stator d is fixed to the fixed support b so as to face the rotor magnet e. The housing c is made of an aluminum material or the like, which is relatively easy to process and has high accuracy. A steel material is usually used for the fixed support b. The housing c and the fixed support b are fixed by adhesion, press fitting, or the like.

[0003]

In the spindle motor having the above-described structure, the height position accuracy of the hub a with respect to the housing c is important as a point of assembling accuracy, and the fixed support b and the housing c are important. Fixing with and is done by carefully adhering or press-fitting using a jig or the like. However, it is becoming more difficult to assemble the spindle motor with high accuracy in response to the recent reduction in size and weight of the recording disk drive. In addition to this, in order to lead the coil lead wire h from the stator d to the outside of the housing c, it has to be inserted into the fixed support b, which is complicated and, as a result, increases the production cost. It was Once again, fixed support b
Once fixed to the housing c, it could not be removed or reassembled and could not be reused if a problem occurred during the production process.

The present invention has been made in view of the above problems existing in the prior art. The problem is that the motor can be assembled accurately even when the motor is made smaller and lighter. Moreover, it is to provide a spindle motor with high workability and high production efficiency.

[0005]

In order to achieve the above object, a spindle motor according to the present invention comprises a hub member having a flange portion, into which a recording disk is mounted, and having a substantially cylindrical shape; A substantially cylindrical sleeve to be fitted; a fixed support; a bearing means provided between the fixed support and the sleeve; a housing for fixedly supporting one end of the fixed support; a rotor A magnet; a stator
A spindle motor in which the hub member is driven to rotate relative to the housing by an electromagnetic action of the rotor magnet and the stator; the rotor magnet is attached to an outer peripheral portion of the sleeve or the hub member. The stator is positioned circumferentially outside of the rotor magnet and disposed in the housing; and the one end of the fixed column, which is fixedly supported by the housing, is formed with a male screw, and A female screw is formed on the housing in correspondence with the above; a slit for screwing the fixed strut is formed at the other end of the fixed strut; and the housing and the fixed strut are
It is screwed and integrally fixed.

[0006]

According to the spindle motor of the present invention, a male screw is formed on one end of the fixed column, and a female screw is formed on the corresponding housing. Therefore, it is possible to assemble the sleeve and the hub member via the bearing means on the fixed column in advance so as to be in a rotationally supported state, and screw this to the housing. The fixed support can be screwed into the housing easily by using a slit provided at the other end of the fixed support. Further, the height of the fixed column with respect to the housing can be freely and easily adjusted by providing a contact with the fixed column or by the degree of screwing, and therefore, accurate assembly can be performed. In addition, since the fixed column and the housing are fixed by screwing, they can be freely attached and detached, and the spindle motor can be reworked or reassembled.

The rotor magnet is arranged on the sleeve or hub member on the rotating member side, and the stator is provided on the housing on the stationary member side. That is, the rotor magnet and the stator are independently provided on the fixed column side and the housing side, and when the spindle motor is assembled, the rotor magnet and the stator can be separately assembled in advance. Therefore, it is possible to configure the spindle motor by various combinations due to the ease of attachment / detachment by screwing the fixed support column and the housing. The coil lead wire of the stator can be easily led out from the housing. As described above, in assembling the spindle motor, it is possible to obtain a spindle motor which can be assembled with high precision even when the motor is made smaller and lighter and has high workability and high production efficiency.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing a part of a magnetic disk drive device, which is a first embodiment of a spindle motor for rotationally driving a magnetic disk, for example. In addition, in the example of the drawing, the magnetic head and its head drive device to be incorporated are omitted. In FIG. 1, the spindle motor 50 is housed in a closed space defined by the cover member 12 and the base member 7, that is, the disk chamber 11. The base member 7 includes
The housing 8 which is a stationary member of the spindle motor 50 is attached.

The housing 8 is made of, for example, an aluminum material and has a substantially shallow dish shape. Housing 8
Has a flange portion 47 having a maximum outer diameter and attached to the base member 7, a flat portion 48, and a boss portion 17 having a thick central portion formed integrally and coaxially. The upper end surface 41 of the base member 7 is used as a mounting height reference surface of the spindle motor, and the corresponding flange portion 47 (lower end surface) of the housing 8 is finished with a predetermined accuracy. Further, the boss portion 17 of the housing 8 is provided with a hole portion 43 penetrating in the vertical direction in the drawing, and the female screw 2 is provided on the inner peripheral portion of the hole portion 43.
5 is formed. The internal thread 25 is formed along the rotation axis 19 and is therefore formed substantially perpendicular to the housing 8.

A fixed support column (shaft) 2 which is fixed to the boss portion 17 of the housing 8 and stands upright is formed of, for example, a steel material into a required shape. A male screw 26 is formed at a corresponding portion of the boss portion 17 of the fixed column 2, that is, a lower end portion of the fixed column 2. The male screw 26 is set to have the same screw pitch so as to be screwed into the female screw 25 formed on the boss portion 17. An annular step portion 21 formed so as to project in the circumferential direction is integrally formed on an upper portion of the male screw 26 of the fixed column 2. The step portion 21 is provided with the lower end surface 49 of the step portion 21 and the boss portion 1 of the housing 8 when the fixed column 2 is screwed to the housing 8.
7, and the upper end surface 46 of 7 contacts. As a result, the fixed column 2 is positioned in height with respect to the housing 8. That is, the stepped portion 21 is used for positioning the fixed column 2. Note that the male screw 26 of these fixed columns 2 and the female screw 25 in the hole 43 that penetrates the housing 8 are sufficiently permeated with a surface treatment liquid for rust prevention after the thread cutting process. . Therefore, generation of dust due to rust from the screw portion is prevented in advance.

Further, the upper end portion of the fixed support column 2 is provided with a hole portion 31 which is coaxially bored and a slit 27 which is provided in the left-right direction in the drawing. The slit 27 is used for screwing the fixed column 2 into the housing 8 by inserting a minus screwdriver, for example, into the slit 27 and screwing the fixed column 2. In addition,
A tube body 28 made of an elastic material such as hard rubber is inserted into and fixed to the hole portion 31.
The cover member 12 abuts and is fixed to the free end of 8, that is, the upper side in the drawing. As a result, the motor vibration that is transmitted from the spindle motor to the cover member 12 via the tube body 28 is effectively blocked.

A pair of bearings 3, 4 (each inner ring portion) is mounted on the outer peripheral portion 35 of the fixed support column 2.
The sleeve 22 is attached through (the outer ring portions of) 4 respectively. The sleeve 22 is made of, for example, magnetic stainless steel and is formed into a substantially cylindrical shape. As a result, the sleeve 22 serves as a rotating member that is rotatably supported by the fixed column 2. A predetermined preload is applied to the bearings 3 and 4 by fixing the step portion 21 of the fixed column 2, the step portion 44 of the sleeve 22, and the inner and outer ring portions thereof. On the outer peripheral wall 36 of the sleeve 22, the rotor magnet 6 is mounted on the lower side in the drawing, and the hub 1 is externally fitted and fixed on the upper side. The rotor magnet 6 is formed in an annular shape, magnetized to a required number of magnetic poles, and fixed to the sleeve 22 with an adhesive or the like.

The hub 1 has a substantially cylindrical shape having a flange portion 16 which is provided in the lower portion so as to project in the circumferential direction, and is made of an aluminum material which has high workability and is easy to obtain processing accuracy.
Two magnetic disks 10 are externally fitted to the outer peripheral side of the hub 1, and are set to a predetermined height by ring-shaped spacers 13 and 14 interposed therebetween. in this case,
The upper end surface 30 of the flange portion 16 serves as a reference surface for the height on which the magnetic disk 10 is mounted, and this reference surface follows the mounting reference surface 41 of the housing 8 described above. The magnetic disk 10 mounted on the hub 1 is fixedly supported by the clamp 15. The clamp 15 is formed of, for example, stainless steel in a ring shape, and is fixed to the outer peripheral wall 61 of the hub 1 by shrink fitting. The lower end of the clamp 15 has a substantially arcuate cross section, and a pressing force acts evenly in the circumferential direction on the spacer 14 located therebelow. The tapered portion 20 formed on the upper end of the hub 1 is a groove formed at equal intervals in the circumferential direction, and a clamp 15 that is shrink-fitted by inserting a jig (not shown) into this groove.
Can be removed.

The hub 1 fitted on the outer peripheral wall 36 of the sleeve 22 is in the height direction of the spindle motor (vertical direction in the drawing).
In the above, the rotor magnet 6 is positioned immediately above the rotor magnet 6 and is fixed by being displaced upward with respect to the height dimension of the sleeve 22. This is because the height of the spindle motor is made as small (thin) as possible and the fitting space between the sleeve 22 and the hub 1 is made as small (small) as possible. That is, this is because the sleep 22 is made of stainless steel and the hub 1 is made of an aluminum material so as to minimize the influence of the shape distortion of the hub 1 due to the difference in thermal expansion between them.

A stator 9 is arranged inside the peripheral wall 5 of the housing 8. The stator 9 is a stator core,
This is composed of an armature coil around which a required winding is wound. The magnetic pole teeth of the stator 9 are arranged to face the rotor magnet 6 in the circumferential direction. The rotor magnet 6 is configured by a so-called inner rotor type brushless DC motor positioned inside the stator 9 in the circumferential direction. Therefore, unlike the conventional outer rotor type spindle motor, in which the stator and the rotor are housed in the hub, they can be set arbitrarily without being restricted by the shape and size of the hub 1. It does not affect the height of the motor. Further, only the stator 9 can be attached to the housing 8 in advance, which is convenient for assembly or process control. Moreover, the coil lead wire 40 of the stator 9 can be easily
Insulating bush 39 embedded in (flat portion 48 in the illustrated example)
After that, it can be easily led out of the motor and connected to the printed circuit board 18 or the like.

A disk chamber 1 in which the bearings 3 and 4 are mounted
Sealing means is provided at a portion communicating with the first side so that unclean air does not leak out. Between the fixed column 2 and the sleeve 22 on which the bearing 3 is mounted, the cap 2
9 is attached. As shown in the drawing, the cap 29 has its inner peripheral end externally fitted and fixed to the outer peripheral surface 35 of the fixed column 2. Then, the hanging portion 34 formed at the outer peripheral end and the step portion 32 of the sleeve 22 are arranged in close proximity to each other, thereby generating a labyrinth sealing function. In addition to the seal 33 provided inside the bearing 3, the cap 29 improves the sealing performance. Since the cap 29 is fixed to the fixed column 2, it can be easily fixed by press fitting or the like, and since the cap 29 itself does not rotate, problems such as contact with the sleep 22 and rotational movement balance do not occur.

A magnetic fluid seal 23 is mounted between the stationary column 2 and the sleep 22 to which the bearing 4 is mounted. The magnetic fluid seal 23 is a ring body 38 made of a non-magnetic material.
It is fixed to the sleeve 22 via the
It is sealed by the magnetic fluid seal layer held between (and the outer peripheral wall 62 of) the stepped portion 21. A protective cap 24 is attached to the outer side (lower side in the figure) of the magnetic fluid seal 23. This protective cap 24 prevents foreign matter from entering the magnetic fluid seal 23 when the hub 1 rotatably supported by the fixed support 2 is screwed into the housing 8.

The spindle motor shown in FIG. 2 is a partial sectional view of the second embodiment according to the present invention. 2 omits common portions of the entire cross-sectional view used in FIG.
Only the characteristic part is shown. In the example already described,
Although the rotor magnet 6 is disposed on the lower outer peripheral wall of the sleeve 22, in the second embodiment, the stainless steel having magnetism is used for the hub 52, and the rotor magnet 55 is provided in the portion located under the hub 52. Has been installed. Therefore, it suffices to mount the rotor magnet 55 on the hub 52 in advance and then fit the sleeve 51 and the hub 52 together in the assembly process. Other functions and effects are similar to those of the first embodiment already described.

As described above, design changes and modifications can be freely made without departing from the spirit of the present invention. That is, in the spindle motor of this embodiment, the housing is fixed, but the housing 8 itself may be applied to a base integrated structure that defines the base member of the apparatus. As the bearings 3 and 4, ordinary ball bearings are shown as an example, but the present invention is not limited to this, and a hydrodynamic bearing including a fluid can be freely selected.

[0020]

In the spindle motor of the present invention, a male screw is formed on one end of the fixed column, and a female screw is formed on the corresponding housing. Therefore, it is possible to assemble the sleeve and the hub member via the bearing means on the fixed column in advance so as to be in a rotationally supported state, and screw this to the housing. Moreover, the fixed support can be easily screwed into the housing by using the slit provided at the other end of the fixed support. Further, the height of the fixed column with respect to the housing can be freely and easily adjusted by providing a contact with the fixed column or by the degree of screwing, and therefore, accurate assembly can be performed. In addition, since the fixed column and the housing are fixed by screwing, they can be freely attached and detached, and the spindle motor can be reworked or reassembled.

Further, the rotor magnet and the stator are independently provided on the fixed column side and the housing side, and they can be preassembled separately at the time of assembling the spindle motor. Further, since the sleeve and the hub are separate bodies, it is possible to freely set the components having different outputs (that is, different thickness dimensions of the stator and the rotor magnet) by arbitrarily setting the occupancy degree of these fittings. . Therefore, it is possible to configure the spindle motor by various combinations due to the ease of attachment / detachment by screwing the fixed support column and the housing. The coil lead wire of the stator can be easily led out from the housing.

As described above, in assembling the spindle motor, it is possible to obtain a spindle motor which can be assembled with high precision even when the motor is made small and lightweight, and which has high workability and high production efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view showing an entire spindle motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a part of a spindle motor according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional spindle motor.

[Explanation of symbols]

 1,52 Hub 22,51 Sleeve 8,57 Housing 3,4 Bearing 2 Fixed support 6,55 Rotor magnet 9,56 Stator 7 Base member

Claims (1)

[Claims] 1. A substantially cylindrical hub member having a collar portion, into which a recording disk is mounted, a substantially cylindrical sleeve into which the hub member is fitted, a fixed column, and the fixed column. And a sleeve that is provided between the sleeve and the sleeve, a housing that fixes and supports one end of the fixed column, a rotor magnet, and a stator, and an electromagnetic wave between the rotor magnet and the stator. In the spindle motor in which the hub member is driven to rotate relative to the housing by the action, the rotor magnet is mounted on an outer peripheral portion of the sleeve or the hub member, and the stator surrounds the rotor magnet. A male screw is formed at one end of the fixed column, which is positioned outside in the direction and is disposed in the housing and is fixedly supported by the housing. And correspondingly, a female screw is formed on the housing, and a slit for screwing the fixed strut is formed at the other end of the fixed strut, and the housing and the fixed strut are formed. Is a screw motor that is fixed integrally with the spindle motor.